#include <iostream>
#include <stack>
using namespace std;

int main(){
	stack<int> st;

	//push three elements into the stack
	st.push(1);
	st.push(2);
	st.push(3);

	//pop and print two elements from the stack
	cout << st.top() << ' ';
	st.pop();
	cout << st.top() << ' ';
	st.pop();

	//modify top element
	st.top() = 77;

	//push two new elements 
	st.push(4);
	st.push(5);

	//pop one element without processing it 
	st.pop();

	//pop and print remainning elements
	while(!st.empty()){
		cout << st.top() << ' ';
		st.pop();
	}
	cout << endl;
	return 0;
}
